import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	A, B, C, D = getlist()
	ans = (A * B * C) % D
	print(ans)

if __name__ == '__main__':
	main()